Xtra, this sounds like a good sistem.
Asking a Captain for jump seat is OK when flight is full, however If seats are available in cabin, I would like to be able to travel without need to ask a Captain.
My bigger problem is security ground staff. Sometimes thay make a problem if I go to Duty Free as operating crew (i.e. FRA). UK can be a problem as well.
Let's say you go to London for a week. Coming in shouldn't be a problem. You can even put yourself on a GenDec so they might not ask you for visa (if you need one). Coming back them might not let you in because you don't have a ticket and you are not operating crew. I'm not sure if GenDec or something else would help, and thats why I've started this t topic.
There also cand be difference between intra EU flights and coming from 3rd world.